The distinctive of non-thermal plasma (NTP) techniques is the efficient use of electrical energy through selective decomposition of the pollutant molecules. NTP processes can simultaneously treat several pollutants at atmospheric pressure with a quite good efficiency at relatively low energy consumption. In this work, NTP was used to remove nitric oxides from a mixture of air, water vapor and helium. Non thermal plasma was generated by dielectric barrier discharge at atmosphere pressure. In this work two different configurations were employed for the process: single dielectric barrier discharge (DBD) and double dielectric barrier discharge (2DBD). The aim of this work is to determine which configuration is most suitable for NOx treatment. A chemical model was developed to observe the species behavior in the plasma and results of numerical simulation demonstrated a good agreement with experimental data of the removal process, achieving more than 96% of NOx removal efficiency. From an electrical diagnosis several experimental parameters such as power, frequency, initial concentration of NOx and specific input energy were tested. To determine the electronic temperature and electronic densities in the plasma, an optical emission spectroscopy study was accomplished.